i worked in the coffee trade (not the same obviously but different )
stores have what is known as their "par" what the suppliers send them on a
weekly bi-weekly or whatever basis.
i imagine the photo retail stores are exactly the same .. they get an amount, the same amount
every month, or whatever, they sell and they get replenished.
if someone goes to the store and buys the whole shelf full of film or paper or chemistry,
the supplier just sends them more at the end of replenish cycle,
it really doesnt' disrupt the store unless 30 customers all arrive and try to buy the sam thing
the next day and the day after that .. i bought 20 boxes of film all at once from b_h
they boxed it and mailed it to me, and had a warehouse of film to sell still ...
i can't imagine ( and i have heard industry experts also say this ) that 1 or 2 or 3 people all buying
a TON of film or paper or ? will disrupt the cycle ...
maybe it does now, IDK ...
the only thing folks who buy a ton at once miss out on might be their favorite supplier having a sale
or wanting to buy from another store if they are having trouble &c ..
i know that was my only regret ... having a ton of film makes it not easy to buy more
when you can get a 100 sheet box of faux fp4 for $25 of buy handful of boxes of j+C
or 1lb of silver nitrate to make one's own strange syrup ..
because of limited shelf space and limited funds and the guilt that you might not use it all up before it goes bad ..